Verifying accuracy of a scanned document

ABSTRACT

A document scanner ( 10 ) includes an input tray ( 30 ) for holding documents ( 20 ) and an input image capture device ( 40 ) for capturing images of the documents ( 20 ) in the input tray ( 30 ) prior to transporting the document for imaging; an output tray ( 150 ) for holding documents ( 20 ) after the documents ( 20 ) exit the scanner; an output image capture device ( 140 ) for capturing images of the output tray; an image processor for determining characteristics of the output tray or characteristic of the documents ( 20 ) before imaging and after the documents ( 20 ) exit the scanner; and scanner functions are modified based on the output tray characteristics or the document characteristics.

CROSS REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly-assigned copending U.S. patent applicationSer. No. 13/714,885, filed Dec. 14, 2012, entitled METHOD OF CAPTURINGAN IMAGE OF A DOCUMENT, by Schaertel et al.; U.S. patent applicationSer. No. 13/714,901, filed Dec. 14, 2012, filed herewith, entitledSYSTEM FOR VERIFYING ACCURACY OF A RASTER SCANNED IMAGE OF A DOCUMENT,by Schaertel et al.; U.S. patent application Ser. No. 13/714,926, filedDec. 14, 2012, entitled SYSTEM FOR CAPTURING AN IMAGE OF A DOCUMENT, bySchaertel et al.; U.S. patent application Ser. No. 12/858,488 (now U.S.Publication No. 2012/0044547), filed Aug. 18, 2010, entitled A DOCUMENTSCANNER, by Schaertel et al.; U.S. patent application Ser. No.12/839,476, filed Jul. 20, 2010, entitled METHOD FOR DOCUMENT SCANNING,by Schaertel et al.; U.S. patent application Ser. No. 12/839,471, filedJul. 20, 2010, entitled A DOCUMENT SCANNER, by Schaertel et al.; andU.S. patent application Ser. No. 12/276,641 (now U.S. Publication No.2010/0127447), filed Nov. 24, 2008, entitled DOCUMENT TRANSPORTAPPARTUS, by Hammen; the disclosures of which are incorporated herein.

FIELD OF THE INVENTION

This invention relates to scanners in general, and in particular toverifying the accuracy of a scanned document.

BACKGROUND OF THE INVENTION

A document scanner moves a document through a transport path and createsa digital image of the document as it moves. The processor for thedocument scanner has preset document characteristics and the operatormust select functions and features to accommodate the specificrequirements for a particular type of document. Alternately, the scannermay default to less efficient settings that will process all documentssince scanners are not typically programmed with specific requirementson a document-by-document basis.

The preset characteristics include document characteristics such assize, weight, texture; and specific application requirements such asresolution and imaging mode, color, simplex, or duplex. In a documentscanner, the documents to be scanned may vary by size, weight, colorcontent, physical condition, or other characteristics, which may requiredifferent scanner features to be enabled or operator actions to beemployed for the most optimal and efficient mode of operation. Priorknowledge of these many different document attributes can enable theproper selection of scanner features to improve the efficiency of thescanning process or enable other features which may provide specificapplications required by a particular type, style, or size of document.Prior knowledge of the documents physical condition can also promptimmediate action from the operator to protect the document or scanner orallow other features within the scanner to perform more reliably.

The exit area of the scanner is used for collecting the scanneddocuments as they exit the transport. A document must also exit thescanner, once it has been imaged, in an orderly fashion. By discerningdocument characteristics in the input area as well as the exit area,characteristics such as, but not limited to, number of documents, theexit area features which control stacking and tracking can be managed.

During the scanning process there are a number of ways in which theinformation extracted from a scanned document may be inaccurate. Thescanned document may be deformed or wrinkled by the document transportsystem, there may be dust or foreign matter on the image capture optics,the document may be skewed or misaligned, or incorrect scanning featuresmay have been selected, but not limited to, all of which may result incapture of inaccurate information during the scanning process. Thereexists a need to verify captured image data, especially in high speeddocument scanners.

There have been attempts in the document printing industry to verifyinformation on printed images, but the requirements for printing adocument are different than the requirements for accurate scanning of adocument. For example, U.S. Publication No. 2008/0013848, discloses aline-by-line scan of a printed document to check for defects such asstreaks or banding in the printed document. U.S. Publication No.2003/0076518, discloses a printer which incorporates a CCD rastercapture device which images the output tray. The captured output imageis compared to data used to print the document.

SUMMARY OF THE INVENTION

Briefly, according to one aspect of the present invention a documentscanner includes verifying accuracy of a raster scanned image of adocument by providing an input tray for holding documents prior toimaging; capturing an image of a document in the input tray with aninput imaging device; transmitting the captured input tray image to animage processor; transporting the document through a document scanner;capturing a scanned image of the document with a raster capture device;transmitting the raster scanned image to the image processor; andverifying the accuracy of the raster scanned image by comparing theraster scanned image of the document to the input tray image of thedocument.

The invention and its objects and advantages will become more apparentin the detailed description of the preferred embodiment presented below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view from the side of a transport for adocument scanner according to the present invention.

FIG. 2 is a perspective view of a scanner output tray according to thepresent invention.

FIG. 3 is a cross-sectional view from the side of a straight throughtransport of a document scanner according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be directed in particular to elements formingpart of, or in cooperation more directly with the apparatus inaccordance with the present invention. It is to be understood thatelements not specifically shown or described may take various forms wellknown to those skilled in the art.

FIG. 1 is a side cross-sectional view of a document scanner 10. As shownin FIG. 1, documents 20 are first placed in the input tray 30 of thescanner 10. The document is moved forward into the scanner 10 by theurging roller 45, then the feed roller 50 while additional documents 20are held back by the separation roller 60. The document 20 continuesthrough the document transport 70, is imaged by the front and rearraster capture devices 80 and 90 respectively, and then moves out of thetransport exit 130 into the output tray 150.

As, or after, the document 20 exits the transport 70 at the transportexit 130, the document 20 and the output tray 150 are imaged by theoutput imaging device 140. The images are sent to the image processor100 to discern document 20 and output tray 150 characteristics.

One output tray 150 characteristic is whether or not there are documents20 present in the output tray 150. If the output tray 150 is determinedto be empty the processor 110 will determine how many documents 20 canbe scanned before the output tray 150 becomes full. Also determining theoutput tray 150 level of documents will be used by the processor 110 tostop scanning if the output tray 150 becomes full. This may happen ifthe operator continues to place documents 20 in the input tray 30 whilescanning without removing documents (20) from the output tray 150.

Another important characteristic is the stacking of the documents 20 inthe output tray 150. If the documents 20 are not laying flat, one on topof another, the processor 110 will stop the scanning process and preventadditional documents 20 from stacking improperly. Improper stacking maybe an indication of the controlled output stacking 120 feature notoperating properly or being inadvertently turned off. Based on theoutput tray 150 characteristics, proper adjustment of the output trayside guides 160 or end stop 170 will be determined. The scanning may bestopped for the operator to adjust the side guides 160 or end stop 170,or an auto adjust feature can be employed to make the correction whilescanning is continued.

Based on document information from an input imaging device 40 thecondition of the document 20 exiting the scanner 10 will be compared tocondition of documents 20 entering the scanner 10 to determine if damageto the document 20, such as bent or torn corners, is occurring withinthe document transport 70, as is shown in FIG. 2. The processor 110 willthen stop the scanning process and alert the operator.

Using the information from the input imaging device 40 the number ofdocuments 20 entering the document scanner 10 can be compared to thenumber of documents 20 exiting the scanner 10. If the number ofdocuments 20 exiting the document scanner 10 does not match the numberof documents 20 entering the document scanner 10 the operator will bealerted to the lost document 20.

In a C-shape document transport 70 the document 20 order can be trackedusing document 20 content captured by the output imaging device 140 inconjunction with the rear raster capture device 90. In document scanner11, shown in FIG. 3, having a straight through document transport 70,the document 20 order can be tracked using the document 20 contentcaptured by the output imaging device 140 in conjunction with the frontraster capture device 80.

In one embodiment of the invention, an image of a document 20 in aninput tray 30 is captured with an input imaging device 40 such as araster capture device, CCD sensor, or CMOS sensor. The captured inputtray image 190 is transmitted to an image processor 100 such as amicroprocessor or a computer. The document is then transported through adocument scanner 10 which captures a raster scanned image 180 of thedocument 20 and the raster scanned image 180 is transmitted to the imageprocessor 100. The image processor 100 verifies the accuracy of theraster scanned image 180 by comparing the raster scanned image 180 ofthe document 20 to the input tray image 190 of the document 20. If theraster scanned image 180 of the document 20 does not match the inputtray image 190 of the document 20, scanner 10 functions may be modifiedor other corrective actions taken. Corrective actions may includerotation of the raster capture device, changing a color capture mode, orcleaning image optics.

The input tray image 190 of the document 20 is captured as an area image210 rather than raster by raster as is typically used to capture theraster scanned image 180 of the document 20. The input tray image 190 ofthe document 20 may be low resolution or high resolution.

In another embodiment of the invention, the document 20 is moved to anoutput tray 150 for holding documents 20 after it exits the scanner 10and an image of the document 20 in the output tray 150 is captured withan output imaging device 140. The captured output tray 150 image istransmitted to the image processor 100 which verifies the accuracy ofthe raster scanned image 180 by comparing the raster scanned image 180of the document 20 to the input tray image 190 of the document 20 andthe output tray image 200 of the document 20.

In yet another embodiment of the invention, an image of a document 20 inan input tray 30 for holding documents 20 is captured as an area image210 rather than raster by raster with an input imaging device 40.Capturing the image as an area image 210 means that an image of theentire document 20 is taken rather than imaging the document 20 rasterby raster, which is the usual way of scanning a document 20. Thecaptured input tray image 190 is transmitted to an image processor 100and the document 20 is transported to an output tray 150. After thefirst document 20 has been transported out of the input tray 30, animage of a second document 20 in the input tray 30 is captured andtransmitted to the image processor 100.

In a further embodiment, an image of the document 20 in the output tray150 is captured with an output imaging device 140 and transmitted to theimage processor 100. The accuracy of the input tray 30 image is verifiedby comparing the input tray image 190 of the document to the output trayimage 200 of the document 20.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the scope of theinvention.

PARTS LIST

-   10 document scanner-   11 document scanner-   20 documents-   30 input tray-   40 input imaging device-   45 urging roller-   50 feed roller-   60 separation roller-   70 document transport-   80 front raster capture device-   90 rear raster capture device-   100 image processor-   110 processor-   120 controlled output stacking-   130 transport exit-   140 output imaging device-   150 output tray-   160 output tray side guides-   170 end stop-   180 raster scanned image-   190 input tray image-   200 output tray image-   210 area image

The invention claimed is:
 1. A method of verifying accuracy of a rasterscanned image of a document comprising: providing an input tray forholding documents prior to imaging; capturing an image of an unaltereddocument in the input tray with an input imaging device; transmittingthe captured input tray image to an image processor; transporting theunaltered document through a document scanner; capturing a rasterscanned image of the unaltered document with a raster capture device;transmitting the raster scanned image to the image processor; verifyingthe accuracy of the raster scanned image by comparing the raster scannedimage of the unaltered document to the captured input tray image of theunaltered document; and modifying scanner functions if the rasterscanned image of the unaltered document does not match the capturedinput tray image of the unaltered document.
 2. The method as in claim 1wherein the scanner functions are selected from a group consisting ofrotation of the raster capture device, changing a color capture mode, orcleaning image optics.
 3. The method as in claim 1 wherein the inputtray image of the unaltered document is captured as an area image ratherthan as a raster scanned image.
 4. The method as in claim 1 wherein theinput tray image of the unaltered document is low resolution.
 5. Themethod as in claim 1 wherein the input tray image of the unaltereddocument is high resolution.
 6. The method as in claim 1 comprising:alerting a document scanner operator if the raster scanned image of thedocument does not match the input tray image of the unaltered document.7. The method as in claim 1 comprising: providing an output tray forholding documents after the documents exit the scanner; capturing anoutput tray image of the document in the output tray with an outputimaging device; transmitting the captured output tray image to theimaging processor; and verifying the accuracy of the raster scannedimage by comparing the raster scanned image of the document to the inputtray image of the unaltered document or the output tray image of thedocument or both.